RESUMO
Significant knowledge gaps exist regarding the fate and transport of persistent organic pollutants like dichlorodiphenyltrichloroethane (DDT) in tropical environments. In Brazil, indoor residual spraying with DDT to combat malaria and leishmaniasis began in the 1950s and was banned in 1998. Nonetheless, high concentrations of DDT and its metabolites were recently detected in human breast milk in the community of Lake Puruzinho in the Brazilian Amazon. In this work, we couple analysis of soils and sediments from 2005 to 2014 at Puruzinho with a novel dynamic floodplain model to investigate the movement and distribution of DDT and its transformation products (dichlorodiphenyldichloroethylene (DDE) and dichlorodiphenyldichloroethane (DDD)) and implications for human exposure. The model results are in good agreement with the accumulation pattern observed in the measurements, in which DDT, DDE, and DDD (collectively, DDX) accumulate primarily in upland soils and sediments. However, a significant increase was observed in DDX concentrations in soil samples from 2005 to 2014, coupled with a decrease of DDT/DDE ratios, which do not agree with model results assuming a post-ban regime. These observations strongly suggest recent use. We used the model to investigate possible re-emissions after the ban through two scenarios: one assuming DDT use for IRS and the other assuming use against termites and leishmaniasis. Median DDX concentrations and p,p'-DDT/p,p'-DDE ratios from both of these scenarios agreed with measurements in soils, suggesting that the soil parameterization in our model was appropriate. Measured DDX concentrations in sediments were between the two re-emission scenarios. Therefore, both soil and sediment comparisons suggest re-emissions indeed occurred between 2005 and 2014, but additional measurements would be needed to better understand the actual re-emission patterns. Monte Carlo analysis revealed model predictions for sediments were very sensitive to highly uncertain parameters associated with DDT degradation and partitioning. With this model as a tool for understanding inter-media cycling, additional research to refine these parameters would improve our understanding of DDX fate and transport in tropical sediments.
Assuntos
DDT/química , Modelos Químicos , Poluentes do Solo/química , Brasil , DDT/análise , Diclorodifenil Dicloroetileno/análise , Diclorodifenil Dicloroetileno/química , Diclorodifenildicloroetano/análise , Diclorodifenildicloroetano/química , Humanos , Malária , Chuva , Solo/química , Poluentes do Solo/análise , Clima TropicalRESUMO
To contribute to the use of the tropical brown mussel Perna perna as a sentinel species for organochlorine pesticides (OCP) and polychlorinated biphenyls (PCB), the present study reports data on the toxicokinetics of these compounds in P. perna. Specifically, the authors present data on OCP and PCB bioaccumulation for eight sampling months from three bays (SE Brazil) and two transplant experiments (each 1 month long). Although seasonality is observed in the total lipid content of the whole soft tissue, with summer samples showing higher values, no such seasonality is observed in the OCP and PCB concentrations bioaccumulated by the mussel P. perna. Because no seasonal effect is observed in the annual OCP and PCB concentrations bioaccumulated by P. perna, the use of this species as a sentinel organism to monitor organochlorinated compounds is encouraged. One month of transplantation is not enough to allow the transplanted specimens to reach the concentrations observed in animals reared at the destination site. Nevertheless, P. perna showed a clear tendency to depurate the DDT metabolites p,p'-DDD and p,p'-DDE after 1 month of transplantation.
Assuntos
Monitoramento Ambiental/métodos , Hidrocarbonetos Clorados/análise , Perna (Organismo)/química , Praguicidas/análise , Poluentes Químicos da Água/análise , Animais , Baías , Brasil , DDT/química , DDT/metabolismo , Diclorodifenil Dicloroetileno/análise , Diclorodifenil Dicloroetileno/metabolismo , Hidrocarbonetos Clorados/metabolismo , Perna (Organismo)/metabolismo , Praguicidas/metabolismo , Bifenilos Policlorados/análise , Bifenilos Policlorados/metabolismo , Estações do Ano , Clima Tropical , Poluentes Químicos da Água/metabolismoRESUMO
Pesticide distribution in the soil profile depends on soil and pesticide properties as well as on the composition of irrigation water. Water containing surfactants, acids or solvents, may alter pesticide desorption from soil. The distribution of organochlorine pesticides (OCPs) in two Argentinean agricultural areas, Pampa and Patagonia, was evaluated. Furthermore, pesticide desorption from aged and freshly spiked soils was performed by the batch technique, using solutions of sodium oxalate and citrate, dissolved organic carbon (DOC), wastewater and surfactants. Patagonian soil showed the highest OCP levels (46.5-38.1 µg g(-1) OC) from 0 to 30 cm depth and the predominance of p,p'-DDE residues reflected an extensive and past use of DDT. Pampean soil with lower levels (0.039-0.07 µg g(-1) OC) was mainly polluted by the currently used insecticide endosulfan. Sodium citrate and oxalate, at levels usually exuded by plant roots, effectively enhanced desorption of p,p'-DDT, p,p'-DDE and α-cypermethrin, while no effects were observed for α-endosulfan and endosulfan sulfate. The non-ionic surfactant Tween 80 behaved similarly to the acids, whereas the anionic sodium dodecyl sulfate enhanced desorption of all pesticides. Increased desorption of the hydrophobic pesticides also occurred when DOC from humic acids but not from sewage sludge or wastewater were used. Soil profile distribution of pesticides was in accordance with results from desorption studies. Data suggest pesticide leaching in Pampean and Patagonian soils, with risk of endosulfan to reach groundwater and that some organic components of wastewaters may enhance the solubilisation and leaching of recalcitrant compounds such as p,p'-DDT and p,p'-DDE.
Assuntos
Monitoramento Ambiental , Hidrocarbonetos Clorados/análise , Praguicidas/análise , Poluentes do Solo/análise , Agricultura , Argentina , DDT/análise , DDT/química , Endossulfano/análise , Endossulfano/química , Hidrocarbonetos Clorados/química , Cinética , Praguicidas/química , Poluentes do Solo/químicaRESUMO
We determined and compared the levels of BHC and DDT isomers and metabolites and HCB in the adipose tissue of 82 cases of autopsies performed at the Morgue Department of Adana Branch of the Council of Forensic Medicine. The relationships between the age, gender, and body mass indexes of cases, and the accumulation of OCs residues were also investigated. Detectable concentrations of p,p'-DDE were found in 100% of adipose tissue samples. Concentrations of OCs in female adipose tissues were significantly higher than male adipose tissues (p < 0.05). The presented work is highly significant, being the first study pointing out the chronic exposure to organochlorine pesticides in Cukurova region.
Assuntos
Tecido Adiposo/metabolismo , Exposição Ambiental/análise , Hidrocarbonetos Clorados/análise , Resíduos de Praguicidas/análise , Tecido Adiposo/química , Adolescente , Adulto , Fatores Etários , Idoso , Índice de Massa Corporal , Cadáver , Canadá , Cromatografia Gasosa , Cidades , DDT/análise , DDT/química , DDT/metabolismo , Diclorodifenil Dicloroetileno/análise , Diclorodifenil Dicloroetileno/química , Diclorodifenil Dicloroetileno/metabolismo , Europa (Continente) , Feminino , Hexaclorobenzeno/análise , Hexaclorobenzeno/química , Hexaclorobenzeno/metabolismo , Humanos , Índia , Masculino , Pessoa de Meia-Idade , Fatores Sexuais , América do Sul , Fatores de Tempo , Turquia , Estados Unidos , Adulto JovemRESUMO
Determination of chlorine ions of pesticides was performed after dechlorination reaction using a palladium/magnesium system. Chlorine ions were quantified by potentiometry with ion-specific electrode. Rates of dechlorination of 100 microg of DDT as a function of reaction time and percent (wt/wt) of palladium deposited on the magnesium particles were determined. The best reaction conditions to DDT dechlorination were achieved with an acetone/water (1:1) solution and DDT reaction with a 0.27% (wt/wt) palladium/magnesium bimetallic system at room temperature for 10 min. The detection limit was of 0.24 microg/mL. This low cost method showed an efficiency of 92% in determining chlorine ions derived from DDT, it is fast, requiring no specialized laboratory equipment.
Assuntos
DDT/análise , Poluição Ambiental/análise , Magnésio/química , Paládio/química , Praguicidas/química , DDT/química , Monitoramento Ambiental , Recuperação e Remediação Ambiental/métodos , Halogenação , Limite de Detecção , PotenciometriaRESUMO
This work evaluates some collateral effects caused by the application of the Fenton process to 1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane (DDT) and diesel degradation in soil. While about 80% of the diesel and 75% of the DDT present in the soil were degraded in a slurry system, the dissolved organic carbon (DOC) in the slurry filtrate increased from 80 to 880mgl(-1) after 64h of reaction and the DDT concentration increased from 12 to 50microgl(-1). Experiments of diesel degradation conducted on silica evidenced that soluble compounds were also formed during diesel oxidation. Furthermore, significant increase in metal concentrations was also observed in the slurry filtrate after the Fenton treatment when compared to the control experiment leading to excessive concentrations of Cr, Ni, Cu and Mn according to the limits imposed for water. Moreover, 80% of the organic matter naturally present in the soil was degraded and a drastic volatilization of DDT and 2,2-bis(4-chlorophenyl)-1,1-dichloroethylene was observed. Despite the high percentages of diesel and DDT degradation in soil, the potential overall benefits of its application must be evaluated beforehand taking into account the metal and target compounds dissolution and the volatilization of contaminants when the process is applied.
Assuntos
Recuperação e Remediação Ambiental/métodos , Poluentes do Solo/química , DDT/química , Diclorodifenil Dicloroetileno/química , OxirreduçãoRESUMO
The degradation of DDT [1,1-bis(4-chlorophenyl)-2,2,2-trichloroethane] and DDE [2,2-bis(4-chlorophenyl)-1,1-dichloroethylene] in highly and long-term contaminated soil using Fenton reaction in a slurry system is studied in this work. The influence of the amount of soluble iron added to the slurry versus the mineral iron originally present in the soil, and the influence of H(2)O(2) concentration on the degradation process are evaluated. The main iron mineral species encountered in the soil, hematite (Fe(2)O(3)), did not show catalytic activity in the decomposition of H(2)O(2), resulting in low degradation of DDT (24%) and DDE (4%) after 6 h. The addition of soluble iron (3.0 mmol L(-1)) improves the reaction reaching 53% degradation of DDT and 46% of DDE. The increase in iron concentration from 3.0 to 24 mmol L(-1) improves slightly the degradation rate of the contaminants. However, similar degradation percentages were obtained after 24 h of reaction. It was observed that low concentrations of H(2)O(2) were sufficient to degrade around 50% of the DDT and DDE present in the soil, while higher degradation percentages were achieved only with high amounts of this reagent (1.1 mol L(-1)).